A child restraint system, also referred to as a child car seat, is used for safely transporting a child within an automotive vehicle, so as to minimize the risk of injury to the child in the event of an accident. The design of the child restraint system is based upon the size of the child. For young infants, a typical rear-facing infant seat comprises a removable carrier adapted to be mounted in a base securely installed in the vehicle. The carrier includes a belt harness to restrain the child within the carrier. A forward-facing seat is recommended for older infants and also may include a belt harness. It is recommended that an older child be seated in a booster seat and restrained by a vehicle seat belt. Since vehicle seat belts are commonly designed for adults, the booster seat includes guides that position the belt to safely restrain the smaller child.
It has been proposed to equip the child restraint system with one or more sensors coupled to an electronic control unit to alert the adult operator if the child restraint system is not properly installed in the vehicle, or not adjusted properly for the child. For example, in a belt-positioning booster seat, the seat may include sensors that detect the belt, so as to enable the control unit to alert the adult operator if the seat belt is not properly positioned. The booster seat is installed in the rear seat of the vehicle. As the child matures, the child may learn to disengage the buckle that secures the vehicle belt. If the child unbuckles the belt while the vehicle is being operated, the adult operator in the front seat may not be aware that the child is no longer properly restrained.
Therefore, a need exists for a child restraint system that monitors the adjustment of the belt while the vehicle is in motion, and alerts the operator in the event that the status or condition of the belt changes so that the belt is no longer properly adjusted to restrain the child.